Twitter, Facebook, YouTube, and Google have taken on roles that don’t suit them.

Twitter, Facebook, YouTube, and Google have grown to encompass duties to the public trust — duties that were never intended to be within their purview in the first place.

A temp worker claims that he “accidentally” deactivated President Trump’s Twitter account for eleven minutes. Facebook enabled advertisers to direct their pitches to the news feeds of almost 2,300 people who expressed interest in the topics of “Jew hater,” “How to burn jews,” or, “History of ‘why jews ruin the world.’” Russian agents bought ads on Google and YouTube to spread disinformation. In response to complaints about hate and abuse, Twitter set up a ludicrously opaque and arbitrary “Trust and Safety Council” that responds pretty quickly to celebrity complaints but leaves other accounts spewing the vilest hate for months.

Twitter, Facebook, YouTube, and Google were not built to differentiate accurate information from inaccurate information, to dispel and counteract hateful voices, or to sniff out and stop disinformation campaigns by foreign intelligence. Despite the hype, slogans, and perhaps even self-delusion, they were not built simply to create a better, more interconnected world.

They were built to make money. None were set up as nonprofits; everyone who works in those companies collects a salary, in many cases a big one with lots of benefits.

None of the billionaire tech titans set out to create a new way for a presidential candidate to communicate to the world without taking questions. None of them foresaw that evil minds would want to livestream a murder or other crimes, nor did they anticipate that creating a new way to make communication easier would also make it easier for terrorists to communicate. None of them intended to create ways for complete strangers to send you hateful or sexually harassing messages, to post your personal address and phone numbers for everyone to see, to send threats, or to whip up a frenzied outrage mob, eager to persuade your employer to fire you for some supposedly controversial statement or belief.

This all developed accidentally or organically, as our society learned what sorts of demons could be unleashed by giving people anonymity and an audience simultaneously.

For a long time, the Big Four could shrug and emphasize that they were platforms, not content creators — technology companies, not media companies. They could argue that they were the modern equivalent of technicians running the printing press or the broadcast equipment, not editors determining the headlines on the front page or anchors making statements behind the news desk. They could shift blame to somebody else if the substance of what they brought to the audience was vile, false, or execrable.

Except . . . like media companies, these big four make most of their revenue from advertising. There’s no charge to set up an account on Twitter, Facebook, or YouTube, and there’s no charge for a Google search. What these companies sell for revenue to advertisers is your eyeballs, so to speak, your attention and focus for a particular amount of time. (All media companies that sell advertising do this.) A common saying about tech companies is, “If you’re not paying for it, you’re the product.”

These four companies have reshaped the news business. For all of its flaws, nothing spreads breaking news faster than Twitter. Facebook and Google combined drive most Web traffic and have enormous effects on the readership and revenue of every news organization. YouTube videos are a de facto extension of television networks; their programming, or at least portions of it, are now available 24/7 through the service (and also on the network’s own branded apps).

There are two ways to address the open sewer that now runs alongside the information superhighway. We can either collectively recognize that Twitter, Facebook, YouTube, and Google are not in the news business, and that the material posted upon them doesn’t deserve to be trusted without verification. People didn’t put great public faith in the truth of declarations found on random handwritten signs on telephone poles or bathroom-stall graffiti, or broadcast by any old voice heard on ham radio. Americans gradually stopped believing the emails from lost Nigerian princes promising millions in exchange for their bank-account information; we can develop a similar appropriate skepticism about what we see on some random Facebook page.

Or Twitter, Facebook, YouTube, and Google can recognize that they are in the news business, whether they like it or not, and start to behave accordingly.

The “old media” had gargantuan flaws, most notably elitism, groupthink, bias, arrogance, and the occasional credulity at a hoax that reaffirmed their preexisting suspicions. But they did have other strengths, among them a more discernible dedication to the truth and a sense of professionalism that reinforced shame and criticism for sharing false information. Getting the story wrong generally led to embarrassment and other significant consequences: Janet Cooke, Jayson Blair, Stephen Glass, Dan Rather. Newspapers, newsmagazines, and television stations took pride in their work.

Few radio stations would give a temp worker the access and authority to interrupt or delete the president’s weekly radio address. Newspapers generally didn’t run the long crank letters alleging vast conspiracies or the manifestos of any old nut who could afford the postage. (You usually would have to kill a few people before a major newspaper would publish your 35,000-word screed.) Maybe the occasional nut would get invited on the local cable-access program, but viewers at home generally took the rants with all of the appropriate grains of salt.

It would be very unprofitable to go to a major media company’s advertising department and say, “The primary audience demographics I’m trying to reach are anti-Semites, those who believe the Jews run the world, and those who want to burn Jews.”

The guys who run these tech giants are smart. But they are not necessarily wise. They have built something that they didn’t really understand, and now they’ve learned the hard way that they couldn’t possibly foresee all the unintended ramifications (a conservative lesson). Their current reckoning will run much smoother for them if they accept responsibility for what appears on their platforms.